Mauritanica

García, Miguel A., Mucina, Ladislav & Nickrent, Daniel L., 2024, A tough nutlet to crack: Resolving the phylogeny of Thesium (Thesiaceae), the largest genus in Santalales, TAXON 73 (1), pp. 190-236 : 202

6. Mauritanica clade (BIPP 1).

— In our sampling this clade contains a single species, Thesium mauritanicum ( Fig. 3D ), from North Africa ( Morocco, Algeria). Its position on the phylogenetic tree ( Fig. 2A ) indicates that it is phylogenetically distinct from the African clade (26). When Battandier (1889) described T. mauritanicum he suggested a relationship with T. bergeri Zucc. (and its synonym T. graecum Boiss. & Spruner ) from W Asia and Greece. However, ITS and chloroplast sequences show that species as part of clade 9. The flowers of T. mauritanicum differ little from Eurasian Thesium species but dense pubescence on the stems, leaves, bracts, abaxial surface of the petals and fruits are uncommon characters in the genus. This clade corresponds to T. ser. Mauritanica Hendrych that also included the Libyan endemic T. erythronicum Pamp. It shares with T. mauritanicum a subshrub habit and reticulate fruits; however, the two species differ in several vegetative and inflorescence features suggesting that it might be related to other Paleoboreal species, possibly in clades 8 or 9.

Figures

Fig. 3. Caption on next page.

Fig. 2. Phylogenetic analysis of Thesium using nuclear ribosomal internal transcribed spacer (ITS) sequences. This tree, rooted with Osyridicarpos and Lacomucinaea (outgroups) gives Bayesian posterior probabilities at the nodes. Clades discussed in the text are numbered. Geographical sources for the sampled taxa are abbreviated as follows: AFN = Northern Africa, AFS = Southern Africa, AFT = Tropical Africa, ASC = Central Asia, ASE = Eastern Asia, ASN = Northern Asia, ASS = Southern Asia, ASW = Western Asia, AUS = Australia, CIS = Canary Islands, EUR = Europe, MAD = Madagascar, SAM = South America, and USA = United States of America.